Propeller shaft



H. L. WAISNER PROPELLER SHAFT Dec. 17, 1935.

Original Filed March 20, 1950 3 Sheets-Sheet l MW Q/M'MW 4 glv MN 9N MNRN// o 0 MN N w 0 NN o QM Q J o o o o o o o o fi NN %N N \N km W w MK I0 I A NW J a m 9% %N Dec. 17,1935. H, w AA ER 2,024,671

PPPPPPPPPPPP FT H. L. WAlSNER PROPELLER SHAFT Original Fi led March 20,19so 3 Sheets-Sheet 3 Patented Dec. 17, 1935 UNITED STATES PATNT OFFICEPROPELLER SHAFT Original application March 20, 1930, Serial No. 437,354,new Patent No. 1,967,487. liiivieled and this application ()ctober 26,1931, Serial No.

2 Claims.

My invention relates to seamless metal tubing for propeller shafts andhas special reference to propeller shafts wherein the inequalities inwall thickness are arranged helically along the wall of the tube,whereby improved static and dynamic balance is impar ed thereto.

In the production of seamless metal tubes, the wall along one side ofthe tube is invariably thicker than the other, thus causing the centerof gravity of the tube to fail to coincide with the geometric center ofthe outer surface thereof. When such tubes are mounted as propellershafts considerable vibration develops as a result of their rotation athigh speeds. These vibration difficulties increase as the rate ofrotation of the shaft increases. As the trend in automobile constructionmoves toward vehicles of greater speed, it becomes increasinglyimportant to have propeller shafts of greater dynamic balance. This Ihave accomplished by twisting the tube between its ends, to helicallyarrange the opposing heavy and light walls of the tube along its length.In this manner, the heavy wall is arranged to lie in substantially equalproportions on all sides of the tube, materially improving the dynamicbalance thereof.

A further source of difiiculty with tubes of this character is that themandrel marks lie parallel to the fiber of the metal which often resultsin materially reducing the strength of the tube. The older methods offorming the tube almost invariably cause decarbonization of the innersurface, further reducing the strength thereof.

One of the objects of the invention is the provision of a propellershaft having the inequalities wall thickness arranged helically alongthe walls of the tube to improve the dynamic balance thereof andincrease its strength.

I have also aimed to provide a seamless propeller shaft wherein themandrel marks lie at an angle with respect to the fiber of the metal.

Other objects and attendant advantages will become, apparent to thoseskilled in the art from the following description and the accompanyingdrawings in which- Figure 1 is an elevation partly in section showingthe complete assembly for drawing and twisting the tube;

Fig. 2 is an enlarged view of the holding and drawing dies;

Fig. 3 is a section on the line 33 of Fig. 1 through the holding die;

Fig. 4 is a section on the line 44 of Fig. 1 showing the rotating die;

((31. ti e-1) Fig. 5 is a section through the tube where it passesthrough the dies;

Fig. 6 is a perspective View of a tube showing in dotted lines thecenter of the heavy side thereof;

Figs. 7 and 8 aresections on the lines 11 and. 88 of Fig. 6 showing themanner in which the heavy section of the wall lies along one side of thetube;

Fig. 9 shows the manner in which the heavy side 10 of the wall of thetube shown in Fig. 6 would be arranged if manufactured by my improvedmethod;

Figs. 19 and ii are sections on the lines |0l0 and llil of Fi 9 alsoshowing the manner in which the heavy side of the wall is directedhelically along the wall of the tube by my improved method; and

Fig. 12 is a section through a second holding die which may be employedfor the second pass 20 of the tube through the drawing mechanism.

The invention contemplates in a general way the provision a propellershaft formed by twisting a seamless tubular metal blank to arrange anyinequalities in wall thickness helically along the walls of the tube andto draw the tubular blank to a desired size in such a manner as to causethe mandrel marks to lie at an angle with respect to the fiber of themetal. Referring to Figs. 6-11, inclusive, the numeral [3 designates atube as formed in the usual manner having a thickened side M, the centerof which is designated by the numeral Hi. Figs. 7 and 8 show the mannerin which this thickened portion I l lies substantially lengthwise of thetube. Fig. 9 shows the manner in which the thickened portion of thetube, as indicated by the line M", will be helically disposed along thewails of the tube when the tube is prepared according to my invention.Figs.

10 and 11 show the manner in which the thickened portion it is disposedaround the center of the tube.

While the invention is not strictly limited to propeller shafts ofseamless tubes it will doubtless be found to be of the greatestadvantage in connection with this type. Though the discussion isdirected particularly to steel tubes, the invention is generallyapplicable to tubes of any metal having sufficient strength to beuseable for this purpose.

This is a division of my copenoling application, Serial No. 437,354,filed March 20, 1930, which resulted in Patent #1,967,487.

Directing attention first to a satisfactory manner of forming thepropeller shafts, a tubular 66 ter with the shaft I9.

blank is first formed according to the well known methods for producingseamless tubing. This tubular blank is then subjected to a twisting stepwherein the walls of the tube are directed circumferentialiy, the resultbeing that the inequalities in wall thickness which, prior to thetwisting step lie parallel to the axis of the outer surface of the tube,are directed in the form of a helix along the walls of the tube. Thisstep contemplates a rotative movement about the longitudinal axis of thetube axially, the full cross-section of metal being displaced and theopposing inner outer surfa of the tube passing through 2, correspond? gand identical movement. This movement is in contradistinction to amovement in which the opposing inner and outer surfaces of the tube havea movement with respect to each other. A movement such as I obtain willthe thicker wall portion of the tube to project in the form of a helixon the surfaces of the tube. The tube is then passed through a reducingdie or dies wherein the tube is reduced to desired diameter. The drawingoperation also causes the irregularities in wall thickness to projectfrom the inner surface of the tube and causes the outer surface to betruly cylindrical. These two steps may be carried on separately orsimultaneously as desired. A suitable machine adapted to carry out thesesteps in a simultaneous manner is shown in Fig. 1, but it will beunderstood that the method and apparatus are fherein disclosed merely byway of illustrating one way in which the shaft may be satisfactorilyformed and I do not intend to limit the scope of the invention to shaftsmade by any particular ethod or apparatus.

Referring to the drawings, Fig. 1 shows a conventional tube drawingbench, designated generally by the numeral 5, having a horizontal bed l5and suitable legs and It? for supporting the bench. A driven shaft Itserves to support a sprocket 20 having an endless driving chain 2|trained therecver. Cogs 22 on the sprocket 26 engage the chain 2| andact to move the lat- A second sprocket, not shown, is supported upon ashaft 23 and serves to support the opposite end of the endless chain 2|.A chuck carriage 24 is supported on the upper side of the bench 55through a plurality of wheels 25 which rest upon the upper edges 25 ofthe bench I5 and a wheel 25a therebeneath. The chuck carriage is adaptedto move from end to end of the bench upon the wheels 25. A draft arm 27is pivotaily supported upon the axle '28 of the rear wheels 25 and isprovided at its outer end with the hooks 25 adapted in its lowerposition to engage with links 3!) of the chain 2|. When so engagedmovement of the chain 2| to vthe right, facing 1, serves to move thechuck 6O carriage 24 toward the right end of the bench Suitable meanssuch as wheel 25a may be provided for maintaining the chuck carriage 24in firm contact w"h the upper edge 25 of the bench l5. A chuck havingjaws 82 therein is rotatably secured within the chuck carriage 24 uponployed for rotating the chuck 3| in timed relation to the drawingmovement as hereinafter described. The forward end 46 of a tubedesignated generally by 4% is engaged by the chuck jaws 32 in anysuitable or desired manner so that 5 rotation of the chuck 3| will causerotation of the forward end 4|) of the tube 4|.

A die support 52 is suitably positioned upon the drawing bench i5 and isfixedly secured. thereto. The forward end of the die support is providedwith a central opening 43 through which the tube 4| is adapted to pass.The opening 43 should be considerably than the tube 4| so that there isno contact between the support 42 and the walls of the tube. A drawingdie 44 is positioned within the die support 42 behind the opening 43 andis provided with suitable faces 45 to reduce the tube 4|, through thedrawing operation, to the desired size. A thrust bearing 45 ispositioned between the die support 42 and the die 44 in such a manner asto permit free rotation of the die 44 against the pressure of thedrawing operations. A holding die 4'! is positioned near the rear end ofthe die support 42 and is provided with a centrally located, straightribbed opening 43 through which the tube 4| is arranged to pass beforeentering the drawing die 44. The diameter of the tube is reduced to acertain extent within this holding die, though this is by no meansessential, the primary object of the die being to prevent rotation ofthe tube 4| at this point. The die 47 is secured within the die support42 by means of a plurality of keys 49 which prevent relative movementbetween the die support 42 and the die 41. The general shape andmounting of the dies 44 and 47 is shown more in detail in Figs. 2, 3,and 4 presently to be discussed.

A mandrel bracket 56 is fixedly secured to the drawing bench l5 and isprovided with a suitable opening 5| within which is rotatably positioneda mandrel bar 52 through nuts 53 positioned upon a threaded end 54 ofthe mandrel bar 52. A thrust bearing 55 serves to permit the freerotation of the mandrel bar 52. The forward end of the mandrel bar 52 isprovided with a mandrel 56 which is shown. more in detail in Fig. 2. Themandrel bar 52 projects inside the tube 4| and supports the mandrel 56within the drawing die 44, the mandrel 56 determining the insidediameter of the tube 4| after the drawing operations have beencompleted. The mandrel bar 52 should be suitably supported to permit asmall amount of lateral movement for the mandrel 56 to accommodate thelatter for the displacement of the thickened portions of the tube 4|.The natural springiness of the mandrel bar will usually be sufiicient toprovide this lateral movement.

Referring to Figs. 2, 3 and 4, which show the two dies and the diesupporting section, straight 60 ribs 51 are shown on the surface of theholding die 41 and a space 58 is provided between the holding die andthe drawing die 44. The mandrel 56 is so positioned that the forward endthereof will be within the drawing die 44 causing the metal of the tube4| to be reduced to pass between the surfaces of the mandrel 56 and thedrawing die 44.

In operation, the forward end 40 of the tube 4| is inserted through thedies 41 and 44 and grasped by the jaws 32 of the chuck 3|, the carriage24 being moved to the left to permit this. The draft arm 21 is thenengaged with the links 30 of the chain 2| and the motor 39 is caused torotate the chuck 3|. The forward end of the tube 4| is, by thisoperation, drawn away from the die support 42 and at the same time isrotated. While the chuck 3| may be rotated in either direction ifdesired, I have found that it ispreferable to turn the forward end 40 ofthe tube in a clockwise direction (viewed from the right hand end of themachine) when propeller shafts are being manufactured, since this givesthe tube a right hand twist and permits the tube to subsequently beemployed to better advantage as a propeller shaft wherein clockwisemotion is being transmitted. As the forward end 40 of the tube 4| isdrawn outward through the dies 4'! and 44 the ribs 51 of the die 41 arepressed into the metal, as shown at 59 in Fig. 5. This prevents the rearend 80 of the tube M from rotating with the rotary motion of the frontend of the tube. There must consequently be a twisting action somewherebetween the holding die 31 and the forward end 40 of the tube. Thistwisting action falls in the space 58 between the holding die GI and thedrawing die 44 since the metal at this point is relatively soft ascompared with the metal after it has passed through the drawing die 44.The drawing die 3 i being rotatable on the thrustbearing 46, therotation of the forward end 40 of the tube ll is transmitted back intothe space 58. The tube between the drawing die 44 and the forward end4!] thereof will be relatively hard as compared with the rear end 60 ofthe tube, due to the cold working operations performed upon it, whilethe metal in the space 58 will be of intermediate hardness, andcertainly will be the softest portion of the tube between the die 4! andthe forward end of the tube. The mandrel 58 is so arranged andpositioned as to be rotatable with the drawing die 44 and with themovement of the forward end 49 of the tube. It is also of such size asto bear against the inner walls of the tube only within the drawing dieM. This leaves the metal in the space 53 free both on its outer andinner surface and, the metal being soft, the tube at this point is bentat an angle on the arc of the circumference, dependent upon the ratiobetween the linear movement of the chuck 3| and the rotary movementthereof. I have found it convenient to draw the tube through the dies ata linear speed of about 10 feet per minute and have provided onerevolution of the chuck 3| to about twenty inches of such linearmovement. bringing the mandrel be into contact with the die 64 andpermitting both of these to rotate with the rotation of the forward end40 of the tube I provide a displacement of the metal within the walls ofthe tube which is different from that obtained by other methods. It willbe plain that the inner and the outer surfaces of the tube 4| aremaintained in fixed relation to each other by the mandrel 56 and the die44. There is consequently no relative movement between these surfaces atthis point. In like manner, the depressions 59 in the tube caused by theribs 51 of the holding die prevents twisting movement of the metalwithin the die ll, consequently movement of the metal in the area 58 issubstantially at right angles to the radius of the outer surface of thetube. This movement is shown by the dotted line 6| of Fig. which isintended to indicate the direction of the fiber of the metal. Theforward ends 62 of the depressions 59 are likewise deflected uponentering the area 58 as shown in Fig. 5. In this manner it will be seenthat the fiber of the metal as well as the inequalities in thickness ofthe tube wall will be directed helically along the wall construction asshown.

of the tube before the tube has been drawn through the drawing die 44.Movement between the tube 4| and the mandrel 55 is entirely linear sincethe mandrel is permitted to rotate with the rotation of the tube. Forthis reason the mandrel marks will not be formed on the inside of thetube in the form of a helix but will extend parallel to the length ofthe tube. Consequently, these mandrel marks will lie across 'the fiberof the metal at an angle and not lie parallel thereto, as is the casewith other types of drawing operations.

Obviously, many changes may be made in the For example, the holding diell may be rotated instead of rotating the chuck 35. However, in thatcase the distance between the die ll and the drawing die 44 should berelatively smali to prevent buckling of the soft tube in the space 52.In like manner both the holding die ii and the chuck 35 might be rotatedin opposite directions thereby accomplishing the same results. Thedistance between the holding die 67 and the drawing die is notparticularly important so long they are not positioned so closelytogether as to result in rupture of the metal. I have found that thisdistance should usually be not less than about one inch. Generallyspeaking, however, in steel tubes the higher the carbon content of thetube metal the greater the space 58 should be. However, the greater thisspace the more waste tube results from the drawing operations. It is,therefore, a compromise as to the proper distance between these twopoints, the distance depending upon the particular conditions underwhich the machine is being operated.

I have found that in the normal operation of the machine with low carbonsteel for example of .08 to .12 C. the tube may be reduced, for example,from a diameter of 2 /2 inches at the rear end 55 to a diameter of twoinches at the forward end of the tube by a single pass through the dies4? and id. The particular dies shown are so arranged that the holdingdie ll reduces the diameter of the tube from 2 inches to substantially2%; inches while the drawing die #14 further reduces the diameter of thetube to two inches. However, when the tube is of high carbon steel it isoften necessary to make more than a single pass of the tube throughthese dies. Under such circumstances the dies el and id are so arrangedas to reduce the size of the tube, for example, from 2 inches at the end68 thereof to 2 inches on the forward end of the tube. The tube is thenannealed and treated in the usual manner for a second drawing operation.In this second drawing operation a smooth faced holding die- 63, such asshown in Fig. 12, is employed. In this instance the face b t of the dieis made considerably longer to increase the friction between the tube lland the die and prevent rotation thereof. In this second pass of themetal through the dies the tube may be given a further amount ofrotation if desired or may be drawn laterally through the dies withoutrotation. On this second pass through the dies the tube is reduced, forexample, from 2 inches to two inches in diameter, dies of suitable sizebeing employed for the purpose.

The mandrel 56 is in contact with the inner wall of the tube ll throughonly a small proportion of its length. This results in a minimum amountof rubbing between the two surfaces as a result of which substantiallyno decarbonization occurs on the inner surface of the tube 4 By thesedrawing operations the physical properties of the tube are substantiallyincreased and the tube may be made substantially lighter be cause ofthis increased strength. The fact that the mandrel marks lie at an anglewith respect to the fiber of the metal materially reduces the danger oftube rupture and weakness, thereby resulting in a tube of substantiallymore valuable properties. Even should decarbonization of the surfaceoccur the fact that the mandrel marks lie across the fiber of the metalsubstantially increases the strength of the tube, at least partiallyrecompensing for the decarbonization of the surface.

The twisting operations, whereby the inequalities in wall t -ickness aredirected helically along the wall of the tube, results in highlyimproved static and dynamic balance thereby enhancing the tube for useas a high speed propeller tube, by causing the line through the centersof gravity to lie in a helix about the axis of the outsidecircumference, instead of parallel with it as would otherwise be thecase.

While I have thus described and illustrated one embodiment of myinvention I am aware that numerous alterations and changes may be madetherein without materially departing from the spirit of the inventionand I do not wish to be limited except as required by the prior art andthe scope of the appended claims.

I claim:

1. A propeller shaft comprising a seamless steel tube having the fiberof the metal helically directed in the walls thereof, the inequalitiesin wall thickness helically directed along the inner surface thereof,and the mandrel marks parallel with the longitudinal center thereof andat an angle with respect to said fiber whereby the balance and thestrength of said shaft is substantially enhanced.

2, A propeller shaft comprising a seamless steel tube having theinequalities in wall thickness helically arranged along the innersurface of said tube to enhance the dynamic balance thereof and themandrel marks lying at an angle with 20 respect to the fiber of themetal to enhance the strength of the tube.

HORACE L. WAISNER.

